THE OXFORD DINOSAUR THAT STARTED IT ALL

In 1824, OUMNH’s very own Megalosaurus became the first named dinosaur.

Discover 200 years of dinosaur science, beginning in the collections of OUMNH.

Just twelve miles from Oxford is the small village of Stonesfield.

Sitting atop seams of Jurassic limestone, Stonesfield was once home to a quarry that supplied Oxfordshire houses with roof tiles.

Inside the Stonesfield Quarry
Inside the Stonesfield Quarry

As the quarriers working at Stonesfield plunged their chisels into the layers of limestone, they would occasionally hit upon strange anomalies —fragments of fossilised skeleton that didn't belong to any living species.

Illustrations of fossil femurs found at Stonesfield
Illustrations of fossil femurs found at Stonesfield

Many of the Stonesfield fossils were acquired by Oxford University’s colleges and museums, attracting the attention of scholars and naturalists. One of these scholars was William Buckland (1784-1856), Oxford University’s first Reader in Geology.

Buckland became particularly interested in a series of giant fossil bones from Stonesfield. These included a large femur, a handful of vertebrae, and a section of toothy jawbone.

Buckland set about trying to work out what kind of giant animal these fossils once belonged to. To do this, he commissioned a series of illustrations from the naturalist Mary Morland and sent them to the French anatomist Georges Cuvier. Buckland, Morland, and Cuvier corresponded about the fossils for several years.

On a visit to Oxford in 1817, Cuvier examined the fossil femur from Stonesfield and concluded that it had belonged to a twelve metre-long reptile. Accordingly, Buckland noticed that the fossil teeth found at Stonesfield were similar in shape to those of modern-day lizards.

Among the other experts who became interested in the Stonesfield fossils was the geologist James Parkinson. In 1822, Parkinson referred to the fossils as belonging to a Megalosaurus, meaning "great lizard".

By 1824, Buckland was ready to publish a scientific description of the fossil animal, officially naming it Megalosaurus.

Little did Buckland know, he had just identified the first of a group of animals that would later become known as 'the dinosaurs'.

Illustrations of Megalosaurus jaw by Mary Morland

Illustrations of fossil ribs and other bones by Mary Morland

Illustrations of Megalosaurus vertebrae by Mary Morland

When Megalosaurus was first described in 1824, the word 'dinosaur' didn't yet exist.

In fact, before 1824, only a handful of other fossil species had received scientific names. Among these were a few fossil reptiles like plesiosaurs and pterosaurs. This meant there was little way of understanding the differences between Megalosaurus and other reptiles from the Mesozoic Era (252-66 million years ago).

As more and more Jurassic reptiles were discovered and identified, it became easier to see the similarities and differences between them. In 1841, the anatomist Richard Owen penned a Report on British Fossil Reptiles. He noted important similarities between Megalosaurus and two fossil reptiles that had been described by then — Iguanodon and Hylaeosaurus. Owen also noticed "peculiarities" that distinguished these reptiles from "modern terrestrial and amphibious [lizards]." He named this ancient group of reptiles the "Dinosauria", meaning "fearfully great lizards".

Over the coming decades, dinosaurs would begin to sink their claws into the public imagination. In 1854, a series of dinosaur sculptures were installed at Crystal Palace Park, cementing dinosaurs' reputation as fearsome prehistoric giants. Working as the project's scientific director, Richard Owen pieced together a reconstruction of Megalosaurus from the Stonesfield fossils, assembling them into a large, long-limbed lizard. Among the Stonesfield fossils were a series of fused lower vertebrae, suggesting to Owen that Megalosaurus walked on all four legs. Benjamin Waterhouse Hawkins, who led the design and construction of these statues, also wrote to Buckland asking for specific measurements of the Megalosaurus fossils.

As more and more dinosaur fossils were discovered, our understanding of Megalosaurus began to change.

By studying other carnivorous dinosaurs,palaeontologists began to predict that Megalosaurus had shorter forelimbs and walked on its two hindlegs. During the early twentieth century, Megalosaurus was depicted as an agile predator with an upright posture.

In more recent decades, palaeontologists have realised that, even though Megalosaurus was bipedal, its posture would have been more horizontal, and it wouldn't have dragged its tail on the ground. Current estimates put Megalosaurus at around nine metres long, with a weight of 1.4 tonnes. Fossilised remains of other carnivorous dinosaurs have been found with filaments that suggest these dinosaurs could have been covered in feathers. Although the mass extinction event at the end of the Mesozoic Era wiped out most dinosaurs, the birds – a group within dinosaurs - survived. Based on modern understanding of the evolutionary steps between Mesozoic dinosaurs and modern birds, it is likely that many dinosaurs, including Megalosaurus, had feathers.

An illustration of Megalosaurus as imagined by Richard Owen based on the fossils found at Stonesfield

The Megalosaurus sculpture at Crystal Park Palace, created in the 1850s

Silhouette based on reconstructions of Megalosaurus from the early 20th century (von Huene, Friedrich. "Carnivorous saurischia in Europe since the Triassic." Bulletin of the Geological Society of America 34, no. 3 (1923): 449-458)

Silhouette based on contemporary reconstructions of Megalosaurus

Life in Jurassic Oxfordshire

Megalosaurus bucklandii

Discover the environment in which Megalosaurus lived, 168 million years ago

_{Artwork by Julius Csotonyi}

Araucarites

Araucarites was a tall conifer that belonged in the same family as the Monkey Puzzle tree (Araucaria araucana), which grows today in Chile and Argentina. It is thought that Araucarites may have formed the diet of long-necked sauropod dinosaurs. Like the Monkey Puzzle tree, its scale-like leaves would probably have been high in energy but difficult to digest.

Phascolotherium

Phascolotherium was one of the first mammals ever discovered from the Mesozoic Era, once known as the Age of Reptiles. Mesozoic mammals were mainly shrew, or rat-sized, with the largest about the size of a badger. Most of them, like Phascolotherium, would probably have been nocturnal, foraging and eating insects at night. It was not until dinosaurs became extinct 66 million years ago that mammals evolved larger body sizes.

William Buckland first reported the presence of mammal jaw bones from Stonesfield in 1824, at the same time as he announced the discovery of Megalosaurus. The specimens caused a great sensation among palaeontologists at the time, as no one had expected to find mammals in such ancient rocks. It took at least 20 years for the Stonesfield jaw bones to be accepted as mammals, with some suggesting they must belong to reptiles or fish. Because of these disagreements, they were nicknamed the “bones of contention”.

Coastal Swamp

The Middle Jurassic (Bathonian Age) of Oxfordshire is thought to have been low-lying coastal swamps, creeks and lagoons, with a hot and humid climate. The fossilised remains of aquatic animals including fish, crocodiles, plesiosaurs, ichthyosaurs, clams and crustaceans have been found as well as land animals.

Pterosaur

Over 200 isolated pterosaur bones have been found in the Taynton Limestone Formation, commonly known as the Stonesfield Slate. The majority of the remains belong to the family Rhamphorhynchidae; mainly small pterosaurs with sharp pointed teeth and long tails.

A recent study by O’Sullivan and Martill (2018) suggests that Stonesfield might potentially be home to the earliest known pterodactyloid fossil.

Dragonfly

Dragonflies were larger in the Jurassic than their modern-day relatives, probably because there would have been less competition for food and lower predation pressure from flying vertebrates (birds and pterosaurs) than there is today. The dragonfly Hemerobioides giganteus which is known from the Stonesfield Slate, had an estimated forewing length of 12 cm, and a total wingspan of around 25 cm.

Meet the Megalosaurus fossils

The Jawbone

This section of lower jawbone was found at Stonesfield at some stage before 1797. It is perhaps the most important Megalosaurus fossil found at the site.

The two pieces of limestone that had surrounded the jawbone were also excavated as they contained fragments of fossil that had been accidentally left behind. In the 1990s, the jawbone and surrounding limestone were designated the type specimens for Megalosaurus bucklandii — chosen to represent the entire species.

The blade-like, serrated teeth embedded in the jawbone tell us that Megalosaurus was a meat eater. Only one of these teeth is fully visible from the outside of the jaw. What happened to the others?

Looking at the limestone that embedded the jawbone, we know that no fossil teeth were accidentally left behind at Stonesfield. This means that this particular Megalosaurus lost its teeth when it was alive or shortly after it died.

*Megalosaurus* lower right jawbone
*Megalosaurus* lower right jawbone

Fragments of fossil material were accidentally left behind when the jawbone was extracted
Fragments of fossil material were accidentally left behind when the jawbone was extracted

A WMG scan of the jaw shows a further six teeth that are sitting partially or fully below the gumline. This tells us that Megalosaurus would have been able to replace their teeth during their lifetime – probably more than once – helping the dinosaur to stay well-armoured despite frequent battles with prey and rivals. Perhaps this particular Megalosaurus died because it lost too many teeth at once and couldn't replace them quickly enough?

Video created by Paul Wilson (University of Warwick)
Supervised by Prof. Mark Williams, Prof. Paul Smith; Dr Alex Attridge
With thanks to Dr Hilary Ketchum; Juliet Hay; Dr Jason Warnett; Prof. Roger Benson